Search Results (74)

The waste dump from the abandoned La Soterraña mine, a former mercury extraction site, contains high concentrations of mercury (Hg) and arsenic (As), which pose a significant environmental risk due to direct exposure to the environment. Given the site’s topography and slope, surface runoff has been identified as the primary mechanism for the dispersal of these toxic elements into nearby watercourses. This study quantifies the amount of Hg and As released into fluvial systems through surface runoff from the waste dump. Historical topographic data, Airborne Laser Exploration Survey public data from the National Plan for Aerial Orthophotographs (1st PNOA-LiDAR) of the Spanish Ministry of Transport, Mobility and Urban Agenda, and high-precision photogrammetric drone surveys were utilized, with centimeter-level accuracy achieved using airborne GNSS RTK positioning systems on the drone. The methodology yields reliable results when comparing surfaces generated from topographic data collected with consistent methodologies and standards. Analysis indicates an environmental release exceeding 1000 kg of mercury (Hg) and 12,000 kg of arsenic (As) between 2019 and 2023, based on high spatial resolution data (GSD = 8 cm). These findings highlight a sustained temporal contribution of chemical contaminants, which imposes serious environmental and biological health risks due to persistent exposure to toxic elements. Full article

Increased precipitation and extreme weather due to climate change can remobilize recent and legacy environmental contaminants from soil, sediment, and sewage overflows. Heavy metals are naturally distributed in Earth’s crust, but anthropogenic activity has resulted in concentrated emissions of toxic heavy metals and deposition in surrounding communities. Cities around the world are burdened with heavy metal pollution from past and present industrial activity. The city of Camden, NJ, represents a valuable case study of climate impacts on heavy metal mobilization in stormwater runoff due to similar legacy and present-day industrial pollution that has taken place in Camden and in many other cities. Various studies have shown that lead (Pb) and other toxic heavy metals have been emitted in Camden due to historic and recent industrial activity, and deposited in nearby soils and on impervious surfaces. However, it is not known if these heavy metals can be mobilized in urban stormwater, particularly after periods of high precipitation. In this study, Camden, NJ stormwater was collected from streets and parks after heavy rain events in the winter and spring for analysis with inductively coupled plasma-mass spectrometry (ICP-MS) to identify lead (Pb), mercury (Hg), cadmium (Cd), and arsenic (As). Lead was by far the most abundant of the four target elements in stormwater samples followed by Hg, Cd, and As. The locations with the highest Pb concentrations, up to 686.5 ppb, were flooded allies and streets between commercial and residential areas. The highest concentrations of Hg (up to 11.53 ppb, orders of magnitude lower than Pb) were found in partially flooded streets and ditches. Lead stormwater concentrations exceed EPA safe drinking levels at the majority of analyzed locations, and Hg stormwater concentrations exceed EPA safe drinking levels at all analyzed locations. While stormwater is not generally ingested, dermal contact and hand-to-mouth behavior by children are potential routes of exposure. Heavy metal concentrations were lower in stormwater collected from parks and restored areas of Camden, indicating that these areas have a lower heavy metal exposure risk. This study shows that heavy metal pollution can be mobilized in stormwater runoff, resulting in elevated exposure risk in industrial cities. Full article

Humans are being exposed to a variety of potentially toxic metal compounds through the diet and/or the intravenous administration of metal-containing medicinal drugs. The organomercurial thimerosal (THI) is a bactericidal that is present in vaccines, but its potential degradation by biomolecules in vivo is incompletely understood. To probe its interaction with low-molecular-weight thiols that are highly abundant within cells, we have employed an LC-based analytical approach in conjunction with a mercury-specific detector. The injection of THI into a C₁₈-HPLC column equilibrated with mobile phases that contained increasing concentrations of up to 15 mM of glutathione (GSH) and 30% acetonitrile revealed the elution of a GS-EtHg adduct in conjunction with THI, as evidenced by electrospray ionization mass spectrometry. These results were confirmed by ¹⁹⁹Hg-NMR spectroscopy. While these results imply a rapid degradation of THI by GSH at physiological pH, it is important to point out that our results were obtained in aqueous solutions containing 30% (v:v) acetonitrile. Further studies need to confirm if the GS-EtHg adduct is also formed in biological fluids. Our results nevertheless demonstrate that GSH and L-cysteine (Cys) are potential targets of THI at physiological pH, which is relevant to better understand its side effects, including previously reported effects on Ca²⁺ channels. Full article

Agricultural soil contaminated with mercury (Hg) poses a serious threat to ecosystems and human health. Although adding an appropriate amount of selenium (Se) can reduce the toxicity and mobility of Hg in soil, Se alone is prone to leaching into groundwater through soil runoff. Therefore, Se-enriched compound fertilizers were developed, and their remediation effect on Hg-contaminated agricultural soil was determined. The Se-enriched compound fertilizers were prepared by combining an organic fertilizer (vinegar residue, biochar, and potassium humate), inorganic fertilizer (urea, KH₂PO₄, ZnSO₄, and Na₂SeO₃), and a binder (attapulgite and bentonite). A material proportioning experiment showed that the optimal granulation rate, organic matter content, and compressive strength were achieved when using 15% attapulgite (Formulation 1) and 10% bentonite (Formulation 2). An analysis of Se-enriched compound fertilizer particles showed that the two Se-enriched compound fertilizers complied with the standard for organic–inorganic compound fertilizers (China GB 18877-2002). Compared with the control, Formulation 1 and Formulation 2 significantly reduced the Hg content in bulk and rhizosphere soil following diethylenetriaminepentaacetic acid (DTPA) extraction by 40.1–47.3% and 53.8–56.0%, respectively. They also significantly reduced the Hg content in maize seedling roots and shoots by 26.4–29.0% and 57.3–58.7%, respectively, effectively limiting Hg uptake, transport, and enrichment. Under the Formulation 1 and Formulation 2 treatments, the total and DTPA-extractable Se contents in soil and maize seedlings were significantly increased. This study demonstrated that Se-enriched compound fertilizer effectively remediates Hg-contaminated agricultural soil and can promote the uptake of Se by maize. The results of this study are expected to positively contribute to the sustainable development of the agro-ecological environment. Full article

The development of deep coalbed methane (buried depth > 2000 m) in the Yan’an block of Ordos Basin is limited by low permeability, the pore structure of the coal reservoir, and the gas–water occurrence relationship. It is urgent to clarify the key control mechanism of pore structure on gas migration. In this study, based on high-pressure mercury intrusion (pore size > 50 nm), low-temperature N₂/CO₂ adsorption (0.38–50 nm), low-field nuclear magnetic resonance technology, fractal theory and Pearson correlation coefficient analysis, quantitative characterization of multi-scale pore–fluid system was carried out. The results show that the multi-scale pore network in the study area jointly regulates the occurrence and migration process of deep coalbed methane in Yan’an through the ternary hierarchical gas control mechanism of ‘micropore adsorption dominant, mesopore diffusion connection and macroporous seepage bottleneck’. The fractal dimensions of micropores and seepage are between 2.17–2.29 and 2.46–2.58, respectively. The shape of micropores is relatively regular, the complexity of micropore structure is low, and the confined space is mainly slit-like or ink bottle-like. The pore-throat network structure is relatively homogeneous, the difference in pore throat size is reduced, and the seepage pore shape is simple. The bimodal structure of low-field nuclear magnetic resonance shows that the bound fluid is related to the development of micropores, and the fluid mobility mainly depends on the seepage pores. Pearson’s correlation coefficient showed that the specific surface area of micropores was strongly positively correlated with methane adsorption capacity, and the nanoscale pore-size dominated gas occurrence through van der Waals force physical adsorption. The specific surface area of mesopores is significantly positively correlated with the tortuosity. The roughness and branch structure of the inner surface of the channel lead to the extension of the migration path and the inhibition of methane diffusion efficiency. Seepage porosity is linearly correlated with gas permeability, and the scale of connected seepage pores dominates the seepage capacity of reservoirs. This study reveals the pore structure and ternary grading synergistic gas control mechanism of deep coal reservoirs in the Yan’an Block, which provides a theoretical basis for the development of deep coalbed methane. Full article

Phytoremediation is based on the use of plants to decontaminate water and soil. In this work, the capacity of high Andean vegetation in the absorption and translocation of heavy metals was analyzed. Species were identified to analyze the presence of metals in roots, stems, and leaves by spectrometry. The translocation factor was determined and analyzed by means of pattern clusters. Based on the floristic inventory, the dominance of the Poaceae and Asteraceae families was determined, and 12 plant species with a high importance value were selected. According to the ICP-AES, mercury (951.07 mg/kg) was determined in the roots of Lachemilla orbiculata, and chromium (21.88 mg/kg) in Carex bonplandii. Arsenic (2.79 mg/kg) was detected as being significantly higher than the values recorded in lowland plants. Cadmium mobility was high in all species, reaching higher values in Baccharis salicifolia (86.28%) and Calamagrostis intermedia (37.16%). Rumex acetocella accumulated lead in leaves (9.27%), while Taraxacum officinale (1.20%) and Calamagrostis intermedia (1.20%) accumulated silicon. Stabilization of chromium, mercury, and sodium was determined in the roots without translocation to higher organs. Finally, cluster analysis showed physiological interactions between metals as a toxicity mitigation mechanism affecting mobility. These findings suggest that they are hyperaccumulator species. Full article

Mercury (Hg) contamination in soils poses significant environmental risks. In response, various nature-based solutions (NbSs) have been developed and studied in the past to treat mercury along with other heavy metals from both point and nonpoint sources. However, various land uses present uncertainties in mercury mobility and treatment efficiency, affecting the scalability of NbS systems. In this study, a systematic review of peer-reviewed articles addressing mercury pollution in NbS soils was conducted. Results revealed that lakeside environments and mining areas are key Hg accumulation zones due to hydrological connectivity and anthropogenic pressures. Constructed wetlands were the most studied NbSs, where those with Acorus calamus and Aquarius palifolius as the main vegetation achieved >90% Hg removal efficiencies. Although NbSs achieved high Hg removal, anaerobic conditions were found to promote MeHg formation, a critical drawback. Moreover, biochar demonstrated potential for immobilizing Hg and reducing bioavailability, though certain types increased MeHg formation under specific redox conditions. Overall, the study highlighted the need for site-specific design, long-term field evaluation, and multidisciplinary strategies to optimize NbS performance for mercury removal. Furthermore, future research on the scalability of mercury-treating NbSs across diverse land uses is recommended to address mercury risks and improve effectiveness. Full article

Mercury is naturally present in soils at trace concentrations, but its cycle is increasingly disrupted by anthropogenic activities, which affect its distribution and behavior. Due to its toxic nature, mercury has become a significant focus in environmental and public health policies. Following the detection of mercury anomalies during groundwater quality monitoring at the Pays de Caux study site (France), a comprehensive multidisciplinary research effort was initiated. This included geological and hydrogeological studies aimed at tracking mercury concentrations in piezometric wells and identifying the sources of these anomalies. This study seeks to assess the groundwater quality and characteristics from ten hydrogeological wells. The evaluation will focus on key hydrogeological parameters, including pH, redox potential (Eh), suspended solids, and groundwater levels, as well as a detailed geochemical analysis of elements such as Hg, Fe, Mn, Zn, Pb, and Cu. The mobilization of mercury and other metallic traces elements is strongly governed by environmental factors. Hydrochemical analyses highlight the complex interplay of various parameters that influence the chemical forms and behavior of mercury in both soil and groundwater. The results from the piezometric measurement campaigns (Pz1 to Pz7) have provided crucial insights, enabling the development of hypotheses about mercury’s behavior in the chalk aquifer. It is hypothesized that impermeable areas may trap groundwater for extended periods, leading to the accumulation and abnormal concentration of mercury. This could cause mercury to be intermittently released, potentially affecting the surrounding environment. Mercury concentrations in groundwater are highly sensitive to pH and redox potential (Eh), with low pH and reducing conditions promoting mercury mobilization and the formation of toxic methylated species. The study suggests the chalk aquifer is generally in equilibrium with mercury, but fluctuations in mercury levels between Pz7 and Pz4 are likely due to the heterogeneity of the clay and geological factors such as mineral composition and fracturing. This research provides insights into mercury transfer in heterogeneous environments and emphasizes the need for continuous hydrogeological monitoring, including piezometer readings, to manage mercury dispersion in the aquifer. Full article

Heavy metal contamination of soil and water is a growing environmental concern, especially mercury, lead, and cadmium. Therefore, fast and reliable methodologies to assess contamination in the field are in demand. However, many methodologies require laborious, expensive, and cumbersome equipment that is not convenient for rapid field analysis. Mobile phone technology coupled with bioluminescent assays provides accessible hands-on alternatives that has already been shown to be feasible. Previously, we demonstrated that firefly luciferases can be harnessed as luminescence color-tuning sensors for toxic metals. An assay based on such a principle was already successfully applied for teaching biochemistry laboratory lessons, which demonstrates the effect of cadmium on enzyme function based on bioluminescence color change. For analytical detection of cadmium in water, here, we developed a novel bioluminescence assay using the cadmium-sensitive Amydetes vivianii firefly luciferase coupled with a cell phone provided with a program to quantify cadmium concentration based on luminescence color discrimination. The application has proven to be efficient with high precision between 0.10 and 2 mM of cadmium, being appliable to diluted water samples (0.1–2 µM) upon concentration and relying on reference cadmium standards values. The light emitted by the reference standards and samples in a dark box is captured by the smartphone’s camera, which, using computer vision, automatically quantifies cadmium according to the RGB color. CadmiLume is a simple and easy luminescent enzymatic biosensor for cadmium contamination in water samples, which instantaneously can provide results with the convenience of a smartphone in the palm of one’s hands. Full article

The simultaneous determination of arsenic and mercury species in human urine is critical for clinical diagnostics and therapeutic monitoring because it reduces the costs, time, and consumption of samples. This study proposes a method of utilizing high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS) for the concurrent analysis of arsenic and mercury species in urine samples. The separation was performed using a Hepu AR 5 μm C₁₈ (250 × 4.6 mm) column, employing a mobile phase composed of 0.1% L-cysteine, 5 mM NH₄H₂PO₄, and 4 mM tetrabutylammonium hydroxide (TBAH). The samples were diluted with water, and matrix interference was reduced through the application of a kinetic energy discrimination (KED) mode. Calibration curves for four arsenic species and three mercury species exhibited strong linearity within the range of 1–20 μg L⁻¹, with correlation coefficients (r) above 0.999. The limits of detection (LOD) ranged from 0.030 to 0.086 μg L⁻¹, while the limits of quantitation (LOQ) were observed to range from 0.10 to 0.29 μg L⁻¹. The spiking recoveries for all species varied from 87.0% to 110.3%, and the intra-day and inter-day relative standard deviations (RSD) were determined to be 1.1–6.0%, and 0.8–9.2%, respectively. These results indicate that the developed method achieves high precision, accuracy, and suitability for clinical applications, offering valuable insights for the diagnosis and treatment of heavy metal exposure. Full article

Adipose tissue, in addition to serving as energy storage, can store lipophilic substances, some of which may pose a health risk if massively mobilized during rapid weight loss. This study aimed to biomonitor inorganic elements in obese patients undergoing bariatric surgery and analyze the role of sociodemographic factors. ICP-MS was employed to quantify 55 elements, including elements identified from the ATSDR’s Substance Priority List and rare-earth elements, in serum samples of 58 obese patients before and after bariatric surgery. A total of 39 out of 55 elements were detected, either before or after surgery, in at least one patient. Serum concentrations of gold, copper, mercury, platinum, and selenium significantly decreased after surgery. Serum concentrations of iron and zinc were significantly lower before surgery. Age, sex, diabetes status, arterial hypertension, and family history of obesity were demographic factors associated with the concentration of elements. Correlation analyses showed significant associations between elements and total lipid concentration or body mass index. Our findings indicate a complex interplay between inorganic elements and body fat and provide relevant information regarding the biomonitoring of these chemical elements in a specific and understudied population. Full article

Background/Objectives: Agricultural soils accumulate inorganic contaminants from the application of phosphate fertilisers. An airstrip located at Belmont Regional Park (BRP), near Wellington, New Zealand, has been found to have a gradient of cadmium contamination due to spillage of superphosphate fertiliser. Methods: Soil samples from the BRP airstrip with a gradient of cadmium contamination, were used as a novel source to explore bacterial communities’ resistance to heavy metals (HMs) and any co-selected antibiotic (Ab) resistance. Results: Differences between BRP soil samples with higher levels of HMs compared to those with lower HM concentrations showed significantly more bacterial isolates resistant to both HMs (40.6% versus 63.1% resistant to 0.01 mM CdCl₂, p < 0.05) and Abs (23.4% versus 37.8% resistant to 20 μg/mL tetracycline, p < 0.05) in soils with higher initial levels of HMs (1.14 versus 7.20 mg kg⁻¹ Cd). Terminal restriction fragment length polymorphism (TRFLP) and 16S rDNA next-generation sequencing profiling investigated changes in HM-induced bacterial communities. Significant differences were observed among the bacterial community structures in the selected BRP soil samples. Conjugative transfer of cadmium resistance from 23–38% of cadmium-resistant isolates to a characterised recipient bacterial strain in vitro suggested many of these genes were carried by mobile genetic elements. Transconjugants were also resistant to zinc, mercury, and Abs. Higher levels of HMs in soil correlated with increased resistance to HMs, Abs, and elevated levels of HMs thus disturbed the bacterial community structure in BRP soil significantly. Conclusions: These findings suggest that HM contamination of agricultural soil can select for Ab resistance in soil bacteria with potential risks to human and animal health. Full article

The pore structure and fluid mobility of gas reservoirs in tight sandstones significantly influence the assessment of reservoir quality and the potential for gas reservoir development. This study focuses on analyzing tight sandstone samples extracted from the Shaximiao Formation in the Central Sichuan Basin. Experimental techniques such as scanning electron microscopy (SEM), high-pressure mercury injection (HPMI), nuclear magnetic resonance (NMR), and micrometer CT (micro-CT) scanning were employed to investigate the pore structure characteristics of tight sandstone reservoirs and their impact on fluid mobility. The findings indicate that the tight sandstones in the study region exhibit three distinct types of pore throat structures, which correspond to varying characteristics in the distribution of mobile fluids. The characteristics of a Class I pore throat structure are a large pore throat, predominantly ranging from 0.1 to 10 μm, exhibiting robust connectivity, and a straightforward pore throat structure. It possesses an average fractal dimension of 2.5347, along with the highest levels of movable fluid saturation and movable fluid porosity, averaging 69.48% and 7.00%, respectively. The pore throat of Class II pore throat structure is concentrated between 0.01 and 0.1 μm, exhibiting weak connectivity and a complicated pore throat structure. The average fractal dimension is 2.6604, while the averages for movable fluid saturation and movable fluid porosity are 46.60% and 3.94%, respectively. The pore throat of Class III pore throat structure is small, exhibiting the lowest connectivity. The coordination number and pore-throat ratio are 1.60 and 4.82, respectively, while the fractal dimension is 2.7388. The fluid mobility is suboptimal, and the mobile fluid saturation is at 19.88%. Nanopores and micropores constituted 30.77% and 30.55%, respectively, serving as the primary pore throats within the tight sandstone reservoir. The microscopic pore structure of tight sandstone is the main factor influencing fluid mobility. Higher-quality pore structures in tight sandstone correlate with enhanced fluid movement. In addition, the physical properties of tight sandstone reservoirs and clay mineral types also have some influence on fluid mobility. There is a direct correlation between the quality of physical characteristics in tight sandstone reservoirs and the amount of fluid that can be easily moved inside them. A rise in chlorite content promotes an increase in moveable fluid content, whereas the opposite is observed for the illite and smectite interlayer (I/S). Full article

Colloidal quantum dots (CQDs) are valuable for their potential applications in optoelectronic devices. However, they are susceptible to thermal degradation during processing and while in use. Mitigating thermally induced sintering, which leads to absorption spectrum broadening and undesirable changes to thin film electrical properties, is necessary for the reliable design and manufacture of CQD-based optoelectronics. Here, low-temperature metal–oxide atomic layer deposition (ALD) was investigated as a method for mitigating sintering while preserving the optoelectronic properties of mercury telluride (HgTe) CQD films. ALD-coated films are subjected to temperatures up to 160 °C for up to 5 h and alumina (Al₂O₃) is found to be most effective at preserving the optical properties, demonstrating the feasibility of metal–oxide in-filling to protect against sintering. HgTe CQD film electrical properties were investigated before and after alumina ALD in-filling, which was found to increase the p-type doping and hole mobility of the films. The magnitude of these effects depended on the conditions used to prepare the HgTe CQDs. With further investigation into the interaction effects of CQD and ALD process factors, these results may be used to guide the design of CQD–ALD materials for their practical integration into useful optoelectronic devices. Full article

Mercury is a naturally occurring metal found in various inorganic and organic forms within the environment. Due to its high toxicity, there is global concern regarding human exposure to this element. The combination of high-performance liquid chromatography and inductively coupled plasma mass spectrometry (HPLC-ICP-MS) is commonly used to analyze the different forms of mercury in a sample due to its high sensitivity and ability to selectively detect mercury. However, the traditional HPLC-ICP-MS methods are often criticized for their lengthy analysis times. In this study, we have refined the conventional approach by transitioning to ultra-high performance liquid chromatography coupled with inductively coupled plasma mass spectrometry (UHPLC-ICP-MS). This modification has resulted in significant reductions in runtime as well as reagent and argon usage, thereby offering a more rapid, environmentally friendly, and cost-effective method. We successfully adapted an HPLC-ICP-MS method to UHPLC-ICP-MS, achieving the analysis of Hg²⁺ and MeHg⁺ within 1 min with a mobile phase consumption of only 0.5 mL and a sample volume of 5.0 µL; this is a major advance compared to HPLC analysis with run times generally between 5 and 10 min. The method’s performance was assessed by analyzing muscle and liver tissue samples (serving as reference material) from fish, demonstrating the versatility of the method in relation to different complex matrices. Full article